Published: August 5, 2026 | Last Modified: August 5, 2026
299Ko's public contact form (plugin/contact/controllers/ContactController.php, home()) sets raw POST field values (name, firstname, email, message) into the page template with no sanitization. The template engine's variable output function (common/Template.php, _show_var()) echoes values with no htmlspecialchars() call, and the sink template (contact.tpl) outputs these values unescaped into an HTML attribute and a textarea. An unauthenticated attacker can submit a payload such as name=">alert(document.domain) to achieve reflected XSS against any visitor who submits or is tricked into auto-submitting the form, including a targeted administrator, enabling session token theft.
This analysis is generated by Ghostwire from NVD, CISA KEV, EPSS, and open-source intelligence data. Verify findings through primary sources before acting.